This invention relates to obturators and to tube assemblies.
The invention is more particularly concerned with obturators for use in tracheostomy tubes.
Tracheostomy tubes are often inserted with the aid of an obturator having a pointed end projecting from the patient end of the tracheostomy tube. The tip of the obturator helps separate tissue, enabling smooth entry of the tube. The obturator also helps stiffen the tube and prevents ingress of tissue into the tube, which could cause blockage. Examples of tracheostomy obturators are described in U.S. Pat. Nos. 4,246,897, 5,222,487, GB2224213, GB2316321 and GB2341102. Any displacement of the obturator from its correct position may make insertion of the tube more difficult and, by reducing the smoothness of the patient end of the assembly, may cause trauma to tissue around the stoma. After insertion, the obturator is pulled out of the machine end of the tube. GB 2316321 describes an obturator with a machine end that clips onto the coupling of the tracheostomy tube, the clip being released by twisting it relative to the tube. In this arrangement, the main body of the obturator is a strap of rectangular section so it is relatively flexible to enable twisting. This obturator works well with tracheostomy tubes that are relatively stiff but it does not provide optimal rigidity with more flexible tubes. Although the obturator could be made stiffer to give the desired rigidity for insertion of the tube, this makes it difficult to twist its clip to release engagement with the coupling of the tracheostomy tube.
It is an object of the present invention to provide an alternative obturator and tube assembly.
According to one aspect of the present invention there is provided an obturator for a curved medical tube, the obturator having a patient end shaped with a tapered nose arranged to protrude from the patient end of the tube and a machine end adapted to fasten with the machine end of the tube, the machine end of the obturator being releasable from engagement with the machine end of the tube by twisting relative to the tube, the obturator being substantially rigid along a major part of its length extending from the patient end, and the obturator having a portion of its length adjacent its machine end that is relatively flexible to permit twisting.
The major part of the obturator preferably has two orthogonal webs. The obturator may comprise a first web extending along the length of the obturator from the patient end nose to the machine end and a second orthogonal web extending along only the more rigid part of the obturator. One web may be arranged to extend along substantially in contact with the outside curve of the tube. The obturator is preferably of T shape in section along its major part. The nose of the obturator may have a bore extending through it along its length. The obturator may be a single-piece moulding of a plastics material. The machine end preferably has two resilient arms extending forwardly on opposite sides and adapted to engage the tube. The machine end of the obturator may have a vent hole therein. The obturator is preferably curved along most of its length with a curvature substantially the same as that of the tube.
According to another aspect of the present invention there is provided a tracheostomy tube assembly comprising a tracheostomy tube and an obturator according to the above one aspect of the invention.
The tracheostomy tube is preferably curved with a constant radius along its length.
A tracheostomy tube assembly including an obturator according to the present invention, will now be described, by way of example, with reference to the accompanying drawings.